The role of genetic testing in accurate diagnosis of X-linked sideroblastic anemia: novel ALAS2 mutations and the impact of X-chromosome inactivation

Abstract X-linked sideroblastic anemia (XLSA) is a hereditary disorder affecting heme biosynthesis, caused by mutations in the ALAS2 gene, which encodes the erythroid-specific enzyme 5-aminolevulinate synthase. This enzyme, which requires pyridoxal 5’-phosphate (PLP) as a cofactor, catalyzes the fir...

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Main Authors: Daniel Jové-Solavera, Marta Rámila, Xènia Ferrer-Cortés, Mireia Olivella, Veronica Venturi, Marta Morado, Ines Hernández-Rodríguez, Aneal Khan, Santiago Pérez-Montero, Cristian Tornador, Ulrich Germing, Norbert Gattermann, Mayka Sanchez
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Language:English
Published: Nature Portfolio 2025-04-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-95590-x
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author Daniel Jové-Solavera
Marta Rámila
Xènia Ferrer-Cortés
Mireia Olivella
Veronica Venturi
Marta Morado
Ines Hernández-Rodríguez
Aneal Khan
Santiago Pérez-Montero
Cristian Tornador
Ulrich Germing
Norbert Gattermann
Mayka Sanchez
author_facet Daniel Jové-Solavera
Marta Rámila
Xènia Ferrer-Cortés
Mireia Olivella
Veronica Venturi
Marta Morado
Ines Hernández-Rodríguez
Aneal Khan
Santiago Pérez-Montero
Cristian Tornador
Ulrich Germing
Norbert Gattermann
Mayka Sanchez
author_sort Daniel Jové-Solavera
collection DOAJ
description Abstract X-linked sideroblastic anemia (XLSA) is a hereditary disorder affecting heme biosynthesis, caused by mutations in the ALAS2 gene, which encodes the erythroid-specific enzyme 5-aminolevulinate synthase. This enzyme, which requires pyridoxal 5’-phosphate (PLP) as a cofactor, catalyzes the first and rate-limiting step of heme synthesis in erythroid cells. XLSA is characterized by hypochromic microcytic anemia and ring sideroblasts in bone marrow, with most patients showing variable degrees of response to pyridoxine supplementation; however, female carriers of ALAS2 mutations often present a distinct clinical phenotype. A comprehensive review of the literature reveals over 100 distinct ALAS2 mutations linked to XLSA in more than 240 families. Here, we report seven new patients (four female cases) initially diagnosed with various conditions, later confirmed to have X-linked Sideroblastic Anemia due to ALAS2 mutations through genetic analysis. Among these, five represent novel ALAS2 mutations, including the first ever reported stop-loss mutation in ALAS2 associated with XLSA rather than X-linked dominant protoporphyria (XLDPP). Computational modelling of six reported cases revealed that four mutations significantly impact protein structure, conformation and cofactor interaction, consistent with our enzymatic assays demonstrating reduced ALAS2 activity. Furthermore, X-chromosome studies in female probands revealed a pronounced skewing of X-chromosome, which may provide an explanation for their distinct clinical manifestations in females.
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spelling doaj-art-c16331fff8f24d7eb7d19c79c03249512025-08-20T02:11:46ZengNature PortfolioScientific Reports2045-23222025-04-0115111410.1038/s41598-025-95590-xThe role of genetic testing in accurate diagnosis of X-linked sideroblastic anemia: novel ALAS2 mutations and the impact of X-chromosome inactivationDaniel Jové-Solavera0Marta Rámila1Xènia Ferrer-Cortés2Mireia Olivella3Veronica Venturi4Marta Morado5Ines Hernández-Rodríguez6Aneal Khan7Santiago Pérez-Montero8Cristian Tornador9Ulrich Germing10Norbert Gattermann11Mayka Sanchez12Iron Metabolism: Regulation and Diseases, Department of Biomedical Sciences, Universitat Internacional de Catalunya (UIC)Iron Metabolism: Regulation and Diseases, Department of Biomedical Sciences, Universitat Internacional de Catalunya (UIC)Iron Metabolism: Regulation and Diseases, Department of Biomedical Sciences, Universitat Internacional de Catalunya (UIC)Biosciences Department, Faculty of Sciences and Technology, University of Vic - Central University of CataloniaIron Metabolism: Regulation and Diseases, Department of Biomedical Sciences, Universitat Internacional de Catalunya (UIC)Service of Hematology, Hospital La PazHematology Department, ICO-Hospital Germans Trias i Pujol, Institut de Recerca Josep CarrerasM.A.G.I.C. (Metabolics and Genetics in Canada)BloodGenetics S.L. Diagnostics in Inherited Blood DiseasesBloodGenetics S.L. Diagnostics in Inherited Blood DiseasesDepartment of Hematology, Oncology and Clinical Immunology, University Hospital Düsseldorf, Heinrich-Heine University DüsseldorfDepartment of Hematology, Oncology and Clinical Immunology, University Hospital Düsseldorf, Heinrich-Heine University DüsseldorfIron Metabolism: Regulation and Diseases, Department of Biomedical Sciences, Universitat Internacional de Catalunya (UIC)Abstract X-linked sideroblastic anemia (XLSA) is a hereditary disorder affecting heme biosynthesis, caused by mutations in the ALAS2 gene, which encodes the erythroid-specific enzyme 5-aminolevulinate synthase. This enzyme, which requires pyridoxal 5’-phosphate (PLP) as a cofactor, catalyzes the first and rate-limiting step of heme synthesis in erythroid cells. XLSA is characterized by hypochromic microcytic anemia and ring sideroblasts in bone marrow, with most patients showing variable degrees of response to pyridoxine supplementation; however, female carriers of ALAS2 mutations often present a distinct clinical phenotype. A comprehensive review of the literature reveals over 100 distinct ALAS2 mutations linked to XLSA in more than 240 families. Here, we report seven new patients (four female cases) initially diagnosed with various conditions, later confirmed to have X-linked Sideroblastic Anemia due to ALAS2 mutations through genetic analysis. Among these, five represent novel ALAS2 mutations, including the first ever reported stop-loss mutation in ALAS2 associated with XLSA rather than X-linked dominant protoporphyria (XLDPP). Computational modelling of six reported cases revealed that four mutations significantly impact protein structure, conformation and cofactor interaction, consistent with our enzymatic assays demonstrating reduced ALAS2 activity. Furthermore, X-chromosome studies in female probands revealed a pronounced skewing of X-chromosome, which may provide an explanation for their distinct clinical manifestations in females.https://doi.org/10.1038/s41598-025-95590-xALAS2X-linked sideroblastic anemiaCongenital sideroblastic anemiaHereditary anemiaRing sideroblastsStop-loss mutation
spellingShingle Daniel Jové-Solavera
Marta Rámila
Xènia Ferrer-Cortés
Mireia Olivella
Veronica Venturi
Marta Morado
Ines Hernández-Rodríguez
Aneal Khan
Santiago Pérez-Montero
Cristian Tornador
Ulrich Germing
Norbert Gattermann
Mayka Sanchez
The role of genetic testing in accurate diagnosis of X-linked sideroblastic anemia: novel ALAS2 mutations and the impact of X-chromosome inactivation
Scientific Reports
ALAS2
X-linked sideroblastic anemia
Congenital sideroblastic anemia
Hereditary anemia
Ring sideroblasts
Stop-loss mutation
title The role of genetic testing in accurate diagnosis of X-linked sideroblastic anemia: novel ALAS2 mutations and the impact of X-chromosome inactivation
title_full The role of genetic testing in accurate diagnosis of X-linked sideroblastic anemia: novel ALAS2 mutations and the impact of X-chromosome inactivation
title_fullStr The role of genetic testing in accurate diagnosis of X-linked sideroblastic anemia: novel ALAS2 mutations and the impact of X-chromosome inactivation
title_full_unstemmed The role of genetic testing in accurate diagnosis of X-linked sideroblastic anemia: novel ALAS2 mutations and the impact of X-chromosome inactivation
title_short The role of genetic testing in accurate diagnosis of X-linked sideroblastic anemia: novel ALAS2 mutations and the impact of X-chromosome inactivation
title_sort role of genetic testing in accurate diagnosis of x linked sideroblastic anemia novel alas2 mutations and the impact of x chromosome inactivation
topic ALAS2
X-linked sideroblastic anemia
Congenital sideroblastic anemia
Hereditary anemia
Ring sideroblasts
Stop-loss mutation
url https://doi.org/10.1038/s41598-025-95590-x
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